The present invention relates to a radiation gas burner with safety device.
More particularly, it relates to radiation gas burner with a safety device with an electrical ignition safety against non-burnt discharge gas and thereby devices for ignition of the gas for interruption of the gas supply during extinguishing of the flame.
Radiation gas burners are known in the art. One of such gas radiation burners is disclosed for example in the German patent document DE 24 40 701 C3. The gas radiation burner disclosed in this document has a porous, perforated burner plate composed for example ceramics and closing from above a mixing chamber of the gas burner. During the operation no flame burns at the upper end of the passage of the perforated or holed burner plate, and the burner plate is brought to glowing and operates as a heat radiator. The temperature of the radiating burner plates is substantially between 900.degree. C. and 950.degree. C., depending on the temperature resistance of the material of the burner plate.
These radiation burners are used for example for space heating, in hot water preparation devices, in drying systems, and in particular in gas cooking devices. Gas cooking devices with gas radiation burners and glass ceramic cooking plates are known in many forms and described for example in the German patent document DE-OS 26 21 801, DE 33 15 745 A1 and U.S. Pat. Nos. 4,083,355 and 4,201,184.
A gas cooking device has one or several gas radiation burners arranged at a distance from one another under a joint known glass ceramic plate. Each burner defines a cooking point on the upper side of the glass ceramic plate. Each individual gas radiation burner is provided with an ignition device and an ignition safety device. The ignition safety device is used for monitoring the presence of the flame. If the flame is extinguished due to operational disturbances, measures have to be taken again for the discharge of non-burnt combustion gas mixture. Several solutions are proposed for this purpose.
The German patent document DE 34 09 334 C2, and European patent document EP - 433 209 A1 disclose a solution in accordance with which the pilot flame used for a back ignition of the burner is thermoelectrically monitored. In the German document DE 26 21 801 C2 the ionization monitoring of the hot discharge gas through the burner plate is provided. In the German document DE G 86 25 847 U1 and DE 37 32 271 C2 the thermoelectric monitoring of the main burner is provided. The German document DE 26 33 849 C3 utilizes a periodic spark ignition of the main burner. Finally, the German document DE 26 41 274 C3 utilizes a glow ignition in continuous operation with the thermoelectric monitoring.
These solutions have the disadvantage that on the one hand they are technically expensive and on the other hand the thermoelectric monitoring for example of the ignition device or the main burner provides only an indirect control of the orderly operation of the burner.